Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 1 | /* |
| 2 | * rtp.c |
| 3 | * |
| 4 | * library functions for the real-time transport protocol |
| 5 | * |
| 6 | * David A. McGrew |
| 7 | * Cisco Systems, Inc. |
| 8 | */ |
| 9 | |
| 10 | |
| 11 | #include "rtp_priv.h" |
| 12 | |
| 13 | #include <stdio.h> |
| 14 | #include <string.h> |
| 15 | |
| 16 | #include <sys/types.h> |
| 17 | #ifdef HAVE_SYS_SOCKET_H |
| 18 | # include <sys/socket.h> |
| 19 | #endif |
| 20 | |
| 21 | #define PRINT_DEBUG 0 /* set to 1 to print out debugging data */ |
| 22 | #define VERBOSE_DEBUG 0 /* set to 1 to print out more data */ |
| 23 | |
| 24 | unsigned int |
| 25 | rtp_sendto(rtp_sender_t sender, const void* msg, int len) { |
| 26 | int octets_sent; |
| 27 | err_status_t stat; |
| 28 | int pkt_len = len + RTP_HEADER_LEN; |
| 29 | |
| 30 | /* marshal data */ |
| 31 | strncpy(sender->message.body, msg, len); |
| 32 | |
| 33 | /* update header */ |
| 34 | sender->message.header.seq = ntohs(sender->message.header.seq) + 1; |
| 35 | sender->message.header.seq = htons(sender->message.header.seq); |
| 36 | sender->message.header.ts = ntohl(sender->message.header.ts) + 1; |
| 37 | sender->message.header.ts = htonl(sender->message.header.ts); |
| 38 | |
| 39 | /* apply srtp */ |
| 40 | stat = srtp_protect(sender->srtp_ctx, &sender->message.header, &pkt_len); |
| 41 | if (stat) { |
| 42 | #if PRINT_DEBUG |
| 43 | fprintf(stderr, "error: srtp protection failed with code %d\n", stat); |
| 44 | #endif |
| 45 | return -1; |
| 46 | } |
| 47 | #if VERBOSE_DEBUG |
| 48 | srtp_print_packet(&sender->message.header, pkt_len); |
| 49 | #endif |
| 50 | octets_sent = sendto(sender->socket, (void*)&sender->message, |
| 51 | pkt_len, 0, (struct sockaddr *)&sender->addr, |
| 52 | sizeof (struct sockaddr_in)); |
| 53 | |
| 54 | if (octets_sent != pkt_len) { |
| 55 | #if PRINT_DEBUG |
| 56 | fprintf(stderr, "error: couldn't send message %s", (char *)msg); |
| 57 | perror(""); |
| 58 | #endif |
| 59 | } |
| 60 | |
| 61 | return octets_sent; |
| 62 | } |
| 63 | |
| 64 | unsigned int |
| 65 | rtp_recvfrom(rtp_receiver_t receiver, void *msg, int *len) { |
| 66 | int octets_recvd; |
| 67 | err_status_t stat; |
| 68 | |
| 69 | octets_recvd = recvfrom(receiver->socket, (void *)&receiver->message, |
| 70 | *len, 0, (struct sockaddr *) NULL, 0); |
| 71 | |
| 72 | /* verify rtp header */ |
| 73 | if (receiver->message.header.version != 2) { |
| 74 | *len = 0; |
| 75 | return -1; |
| 76 | } |
| 77 | |
| 78 | #if PRINT_DEBUG |
| 79 | fprintf(stderr, "%d octets received from SSRC %u\n", |
| 80 | octets_recvd, receiver->message.header.ssrc); |
| 81 | #endif |
| 82 | #if VERBOSE_DEBUG |
| 83 | srtp_print_packet(&receiver->message.header, octets_recvd); |
| 84 | #endif |
| 85 | |
| 86 | /* apply srtp */ |
| 87 | stat = srtp_unprotect(receiver->srtp_ctx, |
| 88 | &receiver->message.header, &octets_recvd); |
| 89 | if (stat) { |
| 90 | fprintf(stderr, |
| 91 | "error: srtp unprotection failed with code %d%s\n", stat, |
| 92 | stat == err_status_replay_fail ? " (replay check failed)" : |
| 93 | stat == err_status_auth_fail ? " (auth check failed)" : ""); |
| 94 | return -1; |
| 95 | } |
| 96 | strncpy(msg, receiver->message.body, octets_recvd); |
| 97 | |
| 98 | return octets_recvd; |
| 99 | } |
| 100 | |
| 101 | int |
| 102 | rtp_sender_init(rtp_sender_t sender, |
| 103 | int socket, |
| 104 | struct sockaddr_in addr, |
| 105 | unsigned int ssrc) { |
| 106 | |
| 107 | /* set header values */ |
| 108 | sender->message.header.ssrc = htonl(ssrc); |
| 109 | sender->message.header.ts = 0; |
| 110 | sender->message.header.seq = (uint16_t) rand(); |
| 111 | sender->message.header.m = 0; |
| 112 | sender->message.header.pt = 0x1; |
| 113 | sender->message.header.version = 2; |
| 114 | sender->message.header.p = 0; |
| 115 | sender->message.header.x = 0; |
| 116 | sender->message.header.cc = 0; |
| 117 | |
| 118 | /* set other stuff */ |
| 119 | sender->socket = socket; |
| 120 | sender->addr = addr; |
| 121 | |
| 122 | return 0; |
| 123 | } |
| 124 | |
| 125 | int |
| 126 | rtp_receiver_init(rtp_receiver_t rcvr, |
| 127 | int socket, |
| 128 | struct sockaddr_in addr, |
| 129 | unsigned int ssrc) { |
| 130 | |
| 131 | /* set header values */ |
| 132 | rcvr->message.header.ssrc = htonl(ssrc); |
| 133 | rcvr->message.header.ts = 0; |
| 134 | rcvr->message.header.seq = 0; |
| 135 | rcvr->message.header.m = 0; |
| 136 | rcvr->message.header.pt = 0x1; |
| 137 | rcvr->message.header.version = 2; |
| 138 | rcvr->message.header.p = 0; |
| 139 | rcvr->message.header.x = 0; |
| 140 | rcvr->message.header.cc = 0; |
| 141 | |
| 142 | /* set other stuff */ |
| 143 | rcvr->socket = socket; |
| 144 | rcvr->addr = addr; |
| 145 | |
| 146 | return 0; |
| 147 | } |
| 148 | |
| 149 | int |
| 150 | rtp_sender_init_srtp(rtp_sender_t sender, const srtp_policy_t *policy) { |
| 151 | return srtp_create(&sender->srtp_ctx, policy); |
| 152 | } |
| 153 | |
| 154 | int |
| 155 | rtp_receiver_init_srtp(rtp_receiver_t sender, const srtp_policy_t *policy) { |
| 156 | return srtp_create(&sender->srtp_ctx, policy); |
| 157 | } |
| 158 | |
| 159 | rtp_sender_t |
| 160 | rtp_sender_alloc() { |
| 161 | return (rtp_sender_t)malloc(sizeof(rtp_sender_ctx_t)); |
| 162 | } |
| 163 | |
| 164 | rtp_receiver_t |
| 165 | rtp_receiver_alloc() { |
| 166 | return (rtp_receiver_t)malloc(sizeof(rtp_receiver_ctx_t)); |
| 167 | } |